First-ever tunnelling stretch of Ph-IV proj completed

New Delhi: In a major milestone for the Delhi Metro, the urban transporter on Friday achieved the completion of its first-ever tunnelling stretch under Phase-IV project of its network, officials said.

This was achieved at Krishna Park Extension on the Janakpuri West R K Ashram Marg corridor with a tunnel boring machine (TBM) breaking through after boring a 1.4 km-long tunnel, they said.

The work on Phase-IV had begun in December 2019 with a groundbreaking ceremony but it was hit after the outbreak of COVID-19 in March 2020.

The lowering of the first-ever TBM under the Phase-IV project had started at Vikaspuri on the Janakpuri West R K Ashram Marg corridor in October 2020, and following the initial drive, the main tunnelling had started early 2021, officials said.

As part of this tunnelling drive, two tunnels (for up

and down movement) of a length of 1.4 km will be bored between Vikaspuri and Krishna Park Extension, officials had then said.

"The main tunnelling work on this stretch was started in April this year after completing the initial drive. Despite the many constraints posed by the COVID-19 pandemic, work was continued and this major milestone could be achieved," the Delhi Metro Rail Corporation (DMRC) said in a statement.

This tunnel breakthrough using a mammoth 73 m-long TBM was achieved

today in the presence of DMRC's Managing Director, Mangu Singh and other senior officials, it said.

A TBM is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can be designed to bore through anything from hard rock to sand.

TBMs have revolutionised the way tunnelling work is done all over the world as now tunnels can be bored without disturbing the buildings and other structures on the surface.